At what stage?

There are many decorating techniques that I have been wanting to experiment with but have found conflicting information on what stage of dryness the ware should be at. It seems individuals have their preference with this as well, I suppose to achieve different looks? For example, if I wanted to make my own stencil and apply it using an underglaze wouldn't the final glaze saturate the edges? So as a rule of thumb, at what stages should underglaze or homemade decals be applied and how does one avoid the decoration being covered or saturated?

Also...I have been carving some platters that I have made and am wondering what the best way to glaze it would be as I am afraid that the carving will be filled in with glaze. I want the carving to be highlighted and in no way covered as well as very contrasted from the rest of the ware.

I apologize for the newbie questions but it seems in ceramics that the answers to the obvious are the hardest to find

I apply underglaze at both the leatherhard and bisque stages . . . if I put it on at leatherhard, I can do any touch-up at bisque stage. It really depends on what result you are looking for . . . sometimes leatherhard works best, othertimes it will be bisque. There is no one answer that fits all situations.

Decals are applied after a glaze firing . . . then the item is refired to cone 016 or so to fuse the decal into the glaze.

To keep the carving from being glazed over, apply some wax to the carving . . . the wax will repel the glaze. Depending on design, location you may have the glaze run over the carving. You'll just have to experiement to find the right solution for what you are doing.

You are correct that we all have our preferences due to what we ware doing. I used underglazes at bone dry and spray with an airbrush.
Different approach than bciske. It is just how I developed for what I am trying to do.

Unfortunately there is no rule of thumb and as you suspect it depends on what look you like, or what look you grow to like after experimenting. Every method has pros and cons.

You can apply underglaze to unfired work but you lose some of the ability to correct mistakes ..e.g. you can just wash the underglaze off of bisque ware.You can fire between underglaze applications to seal the work in place so the next step doesn't ruin it ... but, the wrong glaze could still make it bleed or run. Some underglaze colors are more prone to bleeding on the edges.You can use wax resist or latex resist to protect your carved designs from glaze, but the wrong glaze could still run there during firing.

Every single way of doing it is favored by someone and disliked by someone else. So, I would strongly recommend you make a bunch of test tiles in an L shape and carve some designs on the long side ... then do some tests until you come up with a look you like. That will be your 'right' answer.

Thank you for all the responses! Even though there isn't a definite answer, some of the information gaps I have been running into have been filled. I think I will certainly take Chris' advice and test on some tiles. I am taking a glaze formulation class right now so hopefully that will eventually offer a bit of insight in terms of what I can put over slip, underglaze, etc and not have it bleed or completely cover it up.